Merging semi-crystallization and multispecies iodine intercalation at photo-redox interfaces for dual high-value synthesis

The artificial photocatalytic synthesis based on graphitic carbon nitride (g-C₃N₄) for H₂O₂ production is evolving rapidly. However, the simultaneous production of high-value products at electron and hole sites remains a great challenge. Here, we use transformable potassium iodide to obtain semi-crystalline g-C₃N₄ integrated with the I^-/I₃^- redox shuttle mediators for efficient generation of H₂O₂ and benzaldehyde. The system demonstrates a prominent catalytic efficiency, with a benzaldehyde yield of 0.78 mol g⁻¹ h⁻¹ and an H₂O₂ yield of 62.52 mmol g⁻¹ h⁻¹. Such a constructed system can achieve an impressive 96.25% catalytic selectivity for 2e^- oxygen reduction, surpassing previously reported systems. The mechanism study reveals that the strong crystal electric field from iodized salt enhances photo-generated charge carrier separation. The I^-/I₃^- redox mediators significantly boost charge migration and continuous electron and proton supply for dual-channel catalytic synthesis. This groundbreaking work in photocatalytic co-production opens neoteric avenues for high-value synthesis.